EXTENSIONS OF MENDELIAN INHERITANCE.
Many crosses do not yield simple Mendelian ratios. Instead, the ratios are modified.
These modifications reflect complexities in gene expression not complexities in
inheritance of the genes. In other words,
1. Why is it customary to use pedigrees to determine inheritance patterns in
humans? as opposed to conducting experiments like those by Mendel or
2. Read pages 166-167 in the text and note the characteristics that allow o
To determine the mechanism of inheritance:
Determine whether it is recessive or dominant
by finding the critical mating.
Determine whether it is X-linked or autosomal.
X linked dominant:
Appears more often in females
Does not skip
BIO 390 - GENETICS
FROM GENE TO PHENOTYPE
DOMINANCE, EPISTASIS, GENE
- Genetic and environmental contributions interact to
- Mutations in same the gene usually result in a mutant
phenotype when present together.